This study will evaluate the cost-effectiveness of matching two subject populations (alcohol abuse/dependence and alcohol with cocaine abuse/dependence) to inpatient or outpatient treatment in a private psychiatric setting. A similar matching procedure utilized by McLellan et al. (1983) yielded significant improvement in outcome among male alcohol veterans who had been matched to treatment. However, 100% of the high psychiatric severity subjects could not be matched to an appropriate inpatient psychiatric treatment setting, making it difficult to fully evaluate the effects of matching or inpatient treatment. The proposed study will provide the opportunity to match high psychiatrically severe alcoholics to an appropriate inpatient setting, providing a logica extension to the V.A. study. This procedure will alos be extended to a cocaine and alcohol population that shares the same treatment program. Subjects. Subjects (N = 400) will have a DSM-III-R diagnosis of Alcohol Abuse or Dependence with no other psychoactive substance dependence (N = 200; 100 inpatients/100 outpatients) or a DSM-III-R diagnosis of Alcohol Abuse or Dependence and Cocaine Abuse or Dependence (N = 200; 100 inpatients/100 outpatients). Methods. Prior to referral to a treatment program, research staff will assess the subject on well-defined matching criteria (a) High Psychiatric Severity: A global rating of psychopathology will be used (SCL-90-R); b) Lack of Social Supports: A 4-question assessment developed from questions on the Addiction Severity Index (ASI)) add assign the subject to inpatient or outpatient treatment. Treatment staff will be blind to this assignment and subjects will be treated in the setting that is either deemed appropriate clinically or is dictated by nonclinical factors (e.g., insurance). A group of mismatched subjects (about 50% due to nonclinical factors) will serve as a comparison group for evaluating the effectiveness of treatment matching. Research interviews and biological measures will be done prior to and at the conclusion of inpatient (4 weeks) or intensive outpatient (6 weeks) treatment, monthly during a 12-week Aftercare program, and at 6, 9, and 12 months following discharge from the acute treatment program. The number of therapeutic hours and type of treatment that each subject receives will also be collected.